问题
I am trying to make a frame with a DBGrid that will serve for more than 10 tables with half of its fields as defaults, and other fields exclusive for each table.
As the space for the columns are limited and I do not want to configure each column of each table manually because it is very poor quality work, I was wondering a way to calculate the width of each column by the largest content of a row inside that column, measured by the own component or by the data set.
Does anyone knows the way? Is there out in the world some custom component with that power? I need a solution that implements increase and decrease of size, according to the the visible data in the all visible columns of the grid. My solution so far had a problem with the painting of the selected cell, witch jumps out of the selected dataset row.
Note: Please, do not close my question. It is not about the fit with the grid's width or the form's width. It is about all the columns width to minimize the horizontal scrollbar, but not necessarily hide it.
回答1:
What you have to do is to use the grid's canvas to measure the contents of each column and set the column's width accordingly. You can either iterate through the dataset or use the OnColumnDraw-Event to adjust the width on the fly.
Here's a sample (I had to use an offset of 5 pixels)
procedure TForm7.DBGridDrawColumnCell(Sender: TObject; const Rect: TRect;
DataCol: Integer; Column: TColumn; State: TGridDrawState);
Var
w : Integer;
begin
w := 5+DBGrid.Canvas.TextExtent(Column.Field.DisplayText).cx;
if w>column.Width then Column.Width := w;
end;
procedure TForm7.FormActivate(Sender: TObject);
Var
i : Integer;
begin
// Initialize width
for I := 0 to DBGrid.Columns.Count - 1 do
DBGrid.Columns[i].Width := 5 + DBGrid.Canvas.TextWidth(DBGrid.Columns[i].title.caption)
end;
回答2:
EDITED:
My first code was about fit the columns inside the grid with, with this new code, AutoSizeColumns reads the records to calc the width of each column until MaxRows or Dataset.Eof:
class function TDBGridHelper.AutoSizeColumns(DBGrid: TDBGrid; const MaxRows: Integer = 25): Integer;
var
DataSet: TDataSet;
Bookmark: TBookmark;
Count, I: Integer;
ColumnsWidth: array of Integer;
begin
SetLength(ColumnsWidth, DBGrid.Columns.Count);
for I := 0 to DBGrid.Columns.Count - 1 do
if DBGrid.Columns[I].Visible then
ColumnsWidth[I] := DBGrid.Canvas.TextWidth(DBGrid.Columns[I].Title.Caption + ' ')
else
ColumnsWidth[I] := 0;
if DBGrid.DataSource <> nil then
DataSet := DBGrid.DataSource.DataSet
else
DataSet := nil;
if (DataSet <> nil) and DataSet.Active then
begin
Bookmark := DataSet.GetBookmark;
DataSet.DisableControls;
try
Count := 0;
DataSet.First;
while not DataSet.Eof and (Count < MaxRows) do
begin
for I := 0 to DBGrid.Columns.Count - 1 do
if DBGrid.Columns[I].Visible then
ColumnsWidth[I] := Max(ColumnsWidth[I], DBGrid.Canvas.TextWidth(
DBGrid.Columns[I].Field.Text));
Inc(Count);
DataSet.Next;
end;
finally
DataSet.GotoBookmark(Bookmark);
DataSet.FreeBookmark(Bookmark);
DataSet.EnableControls;
end;
end;
Count := 0;
for I := 0 to DBGrid.Columns.Count - 1 do
if DBGrid.Columns[I].Visible then
begin
DBGrid.Columns[I].Width := ColumnsWidth[I];
Inc(Count, ColumnsWidth[I]);
end;
Result := Count - DBGrid.ClientWidth;
end;
I call it in the DataSet.AfterOpen event:
TGridHelper.AutoSizeColumns(MyDBGrid);
回答3:
Why to use so complicated code? :D Just use this. Its also have 5 px offset.
procedure TForm1.FormActivate(Sender: TObject);
var
i:integer;
begin
for i :=0 to DbGrid1.Columns.Count - 1 do
DbGrid1.Columns[i].width :=5+dbgrid1.Canvas.TextWidth(DbGrid1.Columns[i].Title.Caption);
end;
回答4:
For each column you want to be auto sized set the property SizePriority=1 and for fixed columns set SizePriority=0, in your case only the last column will be auto sized.
Then set property grid.AutoFillColumns=true and that should do it.
回答5:
For TRUEDBGRID .net you can do this:
Private Sub AutoSizeGrid(Grid As C1.Win.C1TrueDBGrid.C1TrueDBGrid)
For Each Sp As C1.Win.C1TrueDBGrid.Split In Grid.Splits
For Each Cl As C1.Win.C1TrueDBGrid.C1DisplayColumn In Sp.DisplayColumns
Cl.AutoSize()
Next
Next
End Sub
For TrueDbGrid ActiveX in vb60 this (this code not include splits):
Public Function APEXGridAutoFix(Grid As TrueOleDBGrid80.TDBGrid)
Dim Col As TrueOleDBGrid80.Column
For Each Col In Grid.Columns
Col.AutoSize
Next
End Function
回答6:
This solution makes all columns expand or shrink according to it's contents, without care if there has to be scroll bars or not, and fix the selected cell drawing malfunction and the the record pointer malfunction.
type
TColumnAutoAdjust = record {Save the information responsible for setting column widths in the grid}
Field: String; {Field name whose information is being stored}
Registered: Boolean; {Indicates whether the size of this column already registered}
Updated: Boolean; {Indicates the actual size of the column was updated}
LastWidth: Integer; {Width indicates the final text of a record of a row column}
CurrWidth: Integer; {Indicates the current size and column width}
Reverter: Integer; {Indicates the greatest width recorded but that is less than the current}
Scrolls: Integer; {Indicates the amount of scrolls present after one width adjustment}
RecNo: Integer; {Indicates which was the record in the table which increased the width of colune}
end;
var { inside the forms private }
gdCols: array of TColumnAutoAdjust; { vetor de ajuste de largura de cada coluna na grade de resultado }
RegisteredCols: Integer; { quantas colunas já foram registradas no controle de ajuste }
gdVisibleRows: Integer; { quantas linhas de cadastros estão visíveis da grade de resultado }
gdVisibleCols: Integer; { quantas colunas de cadastros estão visíveis da grade de resultado }
{ before showing the grid }
RegisteredCols := ResultGrid.Columns.Count;
SetLength(gdCols, RegisteredCols); { determina o tamanho da vetor de controle de colunas }
{ libera a lista }
ResultGrid.Align := alClient;
for i := 0 to RegisteredCols -1 do { inicializando a largura das colunas no tamanho do título de cada }
begin
gdCols[i].Field := ResultGrid.Columns[i].FieldName;
ResultGrid.Columns[i].Width := ResultGrid.Canvas.TextExtent(ResultGrid.Columns[i].Title.Caption).cx;
ResultGrid.Columns[i].Alignment := taLeftJustify;
ResultGrid.Columns[i].Title.Alignment := taLeftJustify;
end;
BrowserQuery.Open;
ResultGrid.Show;
for i := 0 to gdVisibleRows do
begin
BrowserQuery.Next;
ResultGrid.Refresh;
end;
for i := 0 to gdVisibleRows do
begin
BrowserQuery.Prior;
ResultGrid.Refresh;
end;
BrowserQuery.First;
ResultGrid.SetFocus;
end
{ after dataset scroll}
procedure TRecordsBrowserFrameBase.BrowserQueryAfterScroll(DataSet: TDataSet);
var
i, TitleWidth: Integer;
mayAdjustAgain: Boolean; { }
begin
{ ajusta as colunas da grade de resultado a cada movimento da tabela de resultado }
mayAdjustAgain := False;
for i := 0 to RegisteredCols -1 do
begin
if not gdCols[i].Updated then
begin
ResultGrid.Columns[i].Width := gdCols[i].CurrWidth;
gdCols[i].Scrolls := 0;
gdCols[i].Updated := True;
end
else
begin
Inc(gdCols[i].Scrolls);
if (DataSet.RecNo > gdCols[i].RecNo + gdVisibleRows) or (DataSet.RecNo < gdCols[i].RecNo - gdVisibleRows) then
begin
TitleWidth := MaxColSpacing + ResultGrid.Canvas.TextExtent(ResultGrid.Columns[i].Title.Caption).cx;
gdCols[i].LastWidth := gdCols[i].CurrWidth;
gdCols[i].CurrWidth := IFX(gdCols[i].Reverter > TitleWidth, gdCols[i].Reverter, TitleWidth);
gdCols[i].Reverter := IFX(gdCols[i].Reverter > TitleWidth, TitleWidth, 0);
gdCols[i].Updated := False;
mayAdjustAgain := True;
end;
end;
end;
if mayAdjustAgain then
begin
ResultGrid.Refresh;
BrowserQueryAfterScroll(DataSet);
end;
end;
{ on draw column cell }
procedure TRecordsBrowserFrameBase.GridColumnWidthAdjust(Sender: TObject; const Rect: TRect; DataCol: Integer; Column: TColumn; State: TGridDrawState);
var
ColWidth, TextWidth, TitleWidth: Integer;
begin
{ ajusta a capitalização do texto das células }
(Sender as TJvDBGrid).Canvas.Pen.Color := clWhite;
(Sender as TJvDBGrid).Canvas.Rectangle(Rect);
(Sender as TJvDBGrid).Canvas.TextOut(Rect.Left+2, Rect.Top+2, NameCase(Column.Field.DisplayText));
{ ajusta as colunas de uma grade de acordo com o conteúdo das células }
gdVisibleRows := (Sender as TJvDBGrid).VisibleRowCount;
gdVisibleCols := (Sender as TJvDBGrid).VisibleColCount;
TitleWidth := MaxColSpacing + (Sender as TJvDBGrid).Canvas.TextExtent(Column.Title.Caption).cx;
TextWidth := MaxColSpacing + (Sender as TJvDBGrid).Canvas.TextExtent(NameCase(Column.Field.DisplayText)).cx;
ColWidth := Column.Width;
{$WARNINGS OFF}
if (TextWidth > gdCols[DataCol].Reverter) and (TextWidth < ColWidth) then gdCols[DataCol].Reverter := TextWidth;
if (TextWidth > ColWidth) then { texto da célula é mais largo que a coluna }
begin
gdCols[DataCol].Registered := True;
gdCols[DataCol].LastWidth := ColWidth;
gdCols[DataCol].CurrWidth := TextWidth;
gdCols[DataCol].Updated := False;
gdCols[DataCol].RecNo := BrowserQuery.RecNo;
gdCols[DataCol].Reverter := TitleWidth;
Exit;
end;
if (ColWidth < TitleWidth) then { texto da célula é menor que o título da coluna }
begin
gdCols[DataCol].Registered := True;
gdCols[DataCol].LastWidth := ColWidth;
gdCols[DataCol].CurrWidth := TitleWidth;
gdCols[DataCol].Updated := False;
gdCols[DataCol].Reverter := TitleWidth;
Exit;
end;
{$WARNINGS ON}
end;
回答7:
Hello use this procedure.
Procedure AutoSizeColDBGrid(DBGrid:TDBGrid);
var i, ColWidth, ColTextWidth:integer;
begin
if DBGrid.DataSource.DataSet.Active then
begin
DBGrid.DataSource.DataSet.DisableControls;
for i:= 0 to DBGrid.Columns.Count-1 do
begin
ColWidth:=DBGrid.Canvas.TextWidth(DBGrid.Columns[i].Field.DisplayLabel);
DBGrid.DataSource.DataSet.First;
while not DBGrid.DataSource.DataSet.EOF do
begin
ColTextWidth:=DBGrid.Canvas.TextWidth(DBGrid.Columns[i].Field.DisplayText);
if (ColTextWidth > ColWidth) then
begin
ColWidth := ColTextWidth;
end;
DBGrid.DataSource.DataSet.Next;
end;{while}
DBGrid.Columns[i].Width:=ColWidth+10;
end;{for}
DBGrid.DataSource.DataSet.EnableControls;
DBGrid.DataSource.DataSet.First;
end;
end;
回答8:
Use procedure DbGrid1.AutoAdjustColumns and that's it.
来源：https://stackoverflow.com/questions/13292937/how-to-auto-fit-scale-dbgrids-or-other-similar-columns-widths-according-to-it